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1(54
3) The normal symmetrical cirele of the flowers can become
e lliptical.
4) A deviation which, in the case of the Öland-specimens,
be-comes a rule is the reduction of the number of stamens.
As is well known, the number of stamens of the Potentilla-llower
is usually 20, arranged in 3 circles ilO + 5 + ö), sometimes 25—30,
sometimes 15—10. In the groups Fruticosæ and Rupestres, the
stamens, according to Wolf ’page 251 are 25 to 30 in number,
sitting ön the thickened edges of the 5—sided receptacle, and thus
not arranged in 3 circles (see fig. 4 and 8). In the case of the
Öland P. fruticosa, however, the stamens are seldom 25. and
seldom möre, but usually fewer. Ön an examination of 108 flowers
of the type cf 3, the lowest number of stamens proved to be 15
and the average number 22,21. The reduction always takes place in
the case of the larger stamens just opposite the sepals: usually, too,
in the case of those which are nearest to these stamens at the side,
but, ön the contrary. as good as never in the case of those stamens
standing at the base of the petals.
5) I have also observed tetramerous and hexamerous
flowers-The variation in the numerical ground-plan did not affect the
stamens, however, when it was a case of the ordinary reduction.
Individuals with flowers varying in someone or möre of these
wavs, are common. As a rule, such flowers appeared alone
amongst the normal ones ön the bushes, though they were
sometimes found in greater numbers.
The flowers blow, as a rule, in the morning, but, at any time
of the day, and even in the evening. flowers can be observed which
are beginning to open. In this latter case, the opening of the
flower is interrupted in order to be continued the following morning.
The stamens, which, in the bud. are closely pressed together
and have their filaments bent, straighten themselves when the
flower opens and graduallv point möre outwards, in which
process the outer stamens are always somewhat before the inner
ones-The filaments in the young bud are of the same length as the
anthers. and in the open flower they are from 2—5 times that
length. Even before the flower is fully open, the anthers of the
outer stamen open themselves.
The time that the flower requires for opening varies between 30
Svensk Botanisk Tillskrift 1911. 9
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